There were reliable sources saying that if season 8 was the last season then it would be extra episodes because Showtime wanted the series to hit 100 episodes so they could syndicate it. It was also rumored that the show was going to start in the Summer this time to make room for the extra episodes.

I really think that if this was the final season then they would have announced it by now and the season would have been extended to 16-18 episodes to hit 100. The creators have actually stated that they wanted to end the show with season 7 but Showtime wanted more so they're drawing out the end game. So chances are that's what's happening this time too.